Gyroscope erecting system



Nov. 28, 1950 w. A. REICHEL 2,531,826

GYROSCOPE ERECTING SYSTEM Filed Sept. 5, 1946 v 5 Sheets-Sheet 1 INVENTOR M/LA /M/E A. Erma 4 %IMW ATTORNEY Q 1950 w. A. REICHEL 2,531,826

GYROSCOPE ERECTING SYSTEM Filed Sept. 5, 1946 5 Sheets-Sheet 2 INVENTOR YE u z/w/rw/c A. 166767962.

ATTORNEY Nov. 28, 1950 Filed Sept. 5, 1946 w. A. REICHEL GYROSCOPE ERECTING SYSTEM 5 Sheets-Sheet 5 ATTORNEY Nov 28, 1950 w. A. REICHEL 2,531,826

GYROSCOPE ERECTING SYSTEM Filed Sept. 5, 1946 5 Sheets-Sheet 4 AMPL /F /E E INVENTOR MAD/Mm A. Baa/4 ATTORN EY w. A. REICHEL 2,531,826

GYROSCOPE ERECTING SYSTEM 5 Sheets-Sheet 5 Npv. 28, 1950 Filed Sept. 5, 1946 Patented Nov. 28, 1950 UNITED S AT PATENT QFF GYROSCOPE ERECTING srs'rs vl wl dimaznneiehel, Hackensack, N; J assignor,

' by mesne assignments, to Kearfott Company,

Inc., New York, N. 55.,

York

a corporation of New Application September 5, 1946, S erial No. 695.060

This. invention relates to an electrical erecting system-for a vertical indicating gyroscope and has-for an object to provide a system of the above type having novel and improved operating characteristics. Y

'Another object is to provide a system. of the above-type includingcontrol pendulums which are connected to the gyroscope by an electrical synchronous transmission system which controls circuits-for actuating precession torque motors to" maintain the spin axis of the gyroscope vertical:

Another object is to so connect the transmissionsystem that it may be extended. to give indica'tionsnr tocontrol'a member at a distance in accordance with the angular positions of the gyroscope: relative to thecraft on which it is mounted.

"Another: object of 7 this invention is to provide novelrandimproved means for. preventing the gyroscope fromfollowing movements of the pendulums 1dueto excessive acceleration and decelerationforces such as those produced by a change inspeedtorcourse of the craft.

Anotherobject is to provide a system of the above'type in which the'erecting forces are proportional'tothe-displacement.

Various other objects and advantages will be apparent as the nature of theinvention is more iullydiscloseds -Thegyroscope may be mounted on the usual gimbahsuspension'with its axes of movement alignedme'spectively with the pitch and roll axes of the craft. Pitch and roll pendulums are providedandare mounted to maintain true vertical positions at all times except when influenced by acceleration forces. In accordance with the present invention transmitter units of an alter hating. current. synchronous transmission system are'moun-ted onthe twoja-xes of the gyroscope to be actuated by the gyroscope, and other units are controlled by the'pendulums. These units are electricallyconnectedand energized to respond to angular deviations of the direction of the spin axis-of the gyroscope from the positions of the pendulums,- and to produce correction signals proportional to such deviations. These signals are amplified "and are utilized to actuate torque motors-r-which may be of the two-phase induction type and are. connected to apply precessing torquestogthe gyroscope about its mounting axes I in the'proper direction to cause'the gyroscope tocprecess to bring" its spin axis into agreement with the positions of-the' pendulums.

j In normal operaltion the angular variations between the spin axis of the. gyroscope andthe pendulunrarecomparatively small as. the system is operative at all times to restore the gyroscope whenever any variationbegins to appear. However;force' due to acceleration may cause sudden 11. Claims. (01. jigsaw") movements of the pendulums through substantial arcsfrom the true-vertical. In order to prevent the gyroscope' from following these variations suitable provision is made in theainplifier to de-energize the control whenever the signal voltage exceeds a predetermined value corresponding to the variationsnormally expected between the pendulums-and the gyroscope. When the amplifier is thus de-energized the control of the gyroscope by the pendulums is interrupted untilthe acceleration forces have been reduced to a value such that the variation between the pendulums and thespin axis of the gyroscope has been reduced to the'predetermined value. For example;-this value may be as small as a fraction of" a degree,. was much as tendegrees, or even more, depending upon the characteristics of the craft on which it is mounted.-

Although the novel features which are believed to be-characteristic of thi invention are pointed out more particularly in the claims appended heretothe nature of the invention will be better understood by referring to the following description taken in connection with the accompanying v drawings in which a specific embodiment thereof has been set forth for purposes of illustration.

In the drawings:

Fig. 1 is a top plan view, partly in section along thiarlinel-l? of Fig. 3,*showing a gyroscope assembly embodying the present invention;

Fig. 2 isa vertical section taken on the line 2 2' of Fig. 1;

' Fig. 31 is a vertical 3- -3. of Fig. 1;

"Fig; 4 isa schematic diagram of the erection system; and

' Fig. 5 is a schematic diagram of the amplifier.

Referring particularly to the schematic diagram of Fig. 4,a*gyroscope housing l8, containing'the usual gyroscope which is mounted to '1'0- tate about a spin axis I l, is mounted by trunnions l2 and f3 to rotate'in a gimbal ring l''whi'ch in tuln'is mounted by trunnions l5 and I 6 to rotate in a frame' l7 which is adapted to" be secured to asupport 18 which is fixed with respect to the craft. The frame i7 is preferably mounted so that the axis 20 of thetrunnions I2 and i3 is parallel to the fore-and-aft or roll axis of the craft whilethe axis 2'! of the trunnions 5 and l 6 isparall'el'to thetransverseor pitch'axis of the craft a The trunnions l3 and I5 are connected to operate transmitting units 23 and'22 respectively of an alternating current self-synchronous transmission system, and the trunnions I2 and it are geared to torque'motors '24" and 25 respectively. A pendulum -28'ispivota1lymounted to swing about-a shaft-29 theaxis'of which is parallel to the-roll axis 23 and a pendulum 3 0 is pivotally mounted to swing a'bouta shaft'ill the axis of section taken along the line a 3 which is parallel to the pitch axis 2|. The shafts "29 and 3! control the rotors of units 32 and 33 of the transmission system.

The transmitter unit 22 is shown as comprising a Y connected stator winding 38 which remains fixed relative to the frame ii, and a rotor winding 39 which is mounted to turn with the trunnion iii of the gimbal ring i l. The rotor winding 39 is shown as connected by lines 4:! to be energized from an alternating current supply line ii. The stator winding 38 is connected by lines e2 to a Y connected stator winding 43 of the transmission unit 33, rotor winding 44 of which is connected by leads 45 to input terminals 28 and i! of an amplifier to be described. The rotor winding M is mounted to turn with the shaft 3| as the pendulum 30 swings relative to the stator winding 43, which remains fixed relative to the frame I! and the support I8.

The transmitter unit 23 comprises a stator winding which remains fixed relative to the gimbal ring i4 and a rotor winding 5i which is mounted to be turned by the trunnion I3 in accordance with the movements relative to the ring it of the gyro-housing Hi about the axis 2c. The stator winding 50 is connected by leads 52 to a stator winding 53 of transmission unit 32. Rotor winding 55 of the unit 32 is connected by leads 56 to input terminals 5'! and 53 of the amplifier to be described. The rotor winding 5! is connected by leads 59 to the alternating current supply line 4! The electrical elements of the torque motor 25, comprise asquirrel cage induction rotor 68, which is mounted to apply a torque to the gimbal ring i l about the axis 2 I, and a pair of field windings 6i and 62. One end of the field winding 6! is shown as connected by a lead 63 to one side of an alternating current supply line 64, the other side of which is grounded at 65. One end of the field winding 52 is connected by a lead 86 to an output terminal 6'! of the amplifier channel, the other output terminal 63 of which is grounded at 65. The other ends of the windings BI and 62 are connected to a ground lead 69.

The torque motor 21; comprises a squirrel cage rotor M, which ismounted to apply a torque to the gyroscope housing iii about the axis 20, and a pair of field windings H and I2. One end of the winding '12 is connected by a lead 13 to an output terminal M of a second amplifier channel, the other terminal '55 of which is grounded at (55. One end of'the Winding H is connected by a lead it to the supply line 54. The other ends of the windings H and 12 are connected to a ground lead 11.

' The stator winding 38 of the transmitter unit 22 is connected by leads 80 to the stator winding 8! of a unit 82 of the transmission system vhiehmay be remotely located'and is provided with a rotor winding 83 which may be connected by leads 84 to actuate any suitable remote in dicator or follow-up device.

The stator winding 50 of the transmitter unit 23, is connected by leads 85 to the stator winding 85 of a unit 8? of the transmission system which may also be remotely located and may have a rotor winding 83 connected by leads 89 to actuate a suitable remote indicator or follow-up device.

In the operation of the system thus far described the gyroscope in the housing H) is assumed to be positioned with its spin axis I l vertical and thependulums 28 and gravity actuated to maintain vertical positions. Suitable adjustrnents are then made so that zero voltages are induced in the rotor winding 44 of the unit 33 which indicates that the position of the rotor winding 44 corresponds to that of the rotor winding 39 of the transmitter unit 22. Any relative angular displacement between the spin axis ll of the gyroscope and the pendulum 38 about the pitch axis 2i will cause a corresponding relative rotation of the rotor windings 39 and 44 and thereby cause an alternating voltage to be induced in the latter which is of a value proportional to the amount of relative angular displacement between the gyroscope and pendulum and is reversible in phase according to the direction of such displacement. This voltage constitutes a correction signal which is supplied to the input terminals 45 and ii of the amplifier and produces a corresponding amplified alternating voltage at the output terminals 14 and '55. This output voltage is supplied to the control winding 72 of the torque motor 25 and is effective to produce a torque in the rotor iii which is proportional to the angular displacement of the gyroscope from the pendulum and is applied to the gyroscope in a direction to precess the gyroscope about the axis 2| until its spin axis is restored to positional agreement with the pendulum 3i), whereupon the rotor windings 39 and 4e will again be in synchronous positions and no voltage will be induced in the rotor winding 44.

Similarly, if the spin axis H of the gyroscope becomes displaced relative to the pendulum 28 about the roll axis 251, a relative displacement between the rotor windings 5| and 55 takes place, thereby inducing a voltage in the rotor winding 55 which is applied as a signal to the input terminals 5? and 53 of the amplifier and produces an alternating voltage at the output terminals 61 and 58 which is supplied to the control winding 52 of the torque motor 25. A torque proportional to the displacement of the gyroscope is thus produced in the rotor iii? in a direction to precess the gyroscope about the axis 20 until its spin axis H is restored to positional agreement with the pendulum 28, whereupon the rotor windings 5i and 55 are brought into synchronous positions and no signal voltage is developed in the rotor winding 55.

It will be evident from the above description that the spin axis ll of the gyroscope is maintained vertical at all times and any deviation of the spin axis from the positions of the pendulums 28 and 39 is immediately corrected by the transmission system and torque motors above described.

As the displacement of the rotors of the vertical reference units 32 and 33 at the pendulums 28 and 3! and the rotors of the transmitter units '23 and 22 respectively are always the same under conditions of no acceleration there will be no voltage developed in rotors i i and 55 except as required for correcting the position of the gyroscope. However, as the craft or gyro support l8 moves in roll and pitch about the gyro, displacement voltages are developed in rotor windings B8 and 83 respectively and these voltages may be used to actuate any desired romote signalling device or follow-up or control mechanism (not shown) to indicate the instantaneous values of roll and pitch of the craft.

Referring to Fig. 5, the input terminals 46 and ll of the amplifier are shown as connected to the input circuit of an amplifier tube I00. For this purpose the terminal 46 is connected by a lead across the terminal leads H and HI.

I and a blocking condenser I02 to the grid I03 oi the tube 400 and the input terminal 4-] is con;

nected bya lead I04 to the cathode I05 of the tube M0. A resistor I116 and a primary 4.0] of a transformer I68 are connected in .series between the leads. NH and :IM. The secondary 1.09 of the transformer 103 is connected to .a series .circuit includingarectitier I lilanda condenser Ill. The condenser .IIlI is connected across an adjustable tap H2 and one end of a resistor II3 which is connected between the grid I03 and cathode I05 of the tube 4.0.0. The anode N5 of the tube 1:00 is connected through .the primary .I..I.6 of an output transtormer III to the positive terminal of a source I;I.8 .of plate potential indicated as a battery, .thenegative end of which is connected to the cathode I05.

.Qne end of the secondary I of the transformer I-IFI is connected to grids I2I and I22 of amplifier tubes I23 and I24 respectively in parallel. The cathodes i125 and I26 of the tubes I 23and I24 respectively are connected by a commonlead I21 .to an adjustable tap I 2. 8 of a resistor 42-9.

The anode .I'32 .of the tube I23 is connected by a. lead I533 to one end of .a saturating winding I34 of asaturable core transformer I35 having a. primary winding 1-35 and a secondary winding I33. The anode i ls of the amplifier tube I24 is connected by a lead I4I to one end of a saturating winding L42 of a saturaole core transformer I43 having a primary winding I44 and a secondary winding i415.

The primary 15.0.01? a transformer I5I is connected-iby-leads I52 and -,I 53 to a suitable source of power supply suchas a 115 volt 400 cycle source which is in phase with the voltage in the supply linev 4".I (Fig. 4"). The transformer -I5I is provided with two secondaries I54 and L55. The resistor I=29 is connected across the secondary I55, the center ,pointof which i -connected by a lead I56 to onecnd of the secondary I54. The other end of the secondary IE4 is connected by a lead I58 to the return side of the saturating winding I42 of the transformer i i- .3. The return side of the saturating winding 13;! of the transformer I35 is. con-nected by a lead Itil to the power supply lead .452 on the primary side of the transformer I54. The end of the primary I68, which is connected to lead I53 of the power supply and the end of the secondary I 54 which is connected to lead I56 are joined by a lead I-6I. The return side of the secondary I20 of the transformer II-I is; connected by a lead I62 to the power supply lead I53.

The primaries I 36 and I44 of the transformers I35 and I43 are. connected in series :by leads I63, 64 and 5126550 power supply terminals I66 and I6! which are connected to the power supply line 6.4 -proyiding suitable operating voltage, such as 65 .volts, 400 cy les.

Thesecondaries I31 .and I45 of the transformers H5 and I43 are connected in series opposition by leads-it!) and HI to the output terminals 14 and 1.5. oft-he amplifier. A condenser I1 2 'for control.- ling the phase of the output signal is connected A condenser IFI'3 is also shown as connected across the secondary 120 of the transformer H1.

The channel between the input terminals 5? and .58 and the output terminals 6'! and :68 is similar to that described above and the elements have been givencorresponding reference numerals with the suffix a."

In-the operation of this amplifier the signal at the input terminals 45 and .41 produces achange in the grid potential of the amplifier tube I00 which causes. a corresponding change inthe current flowing in the output circuit of this tube. This output current is supplied through the trans; former IIT to the tubes .123 and I-24 .and causes current flow in the saturating windings I34 and I42 of the saturable core transformers I35 and I43. The. connections are .such that with no sis..- nal supplied. to the input of the amplifier tube I 0.0 equalcurrents how in the saturating windings I 3.4 and I42 in the output circuits of the tubes .I23 and I 24. When .a signal is applied to the input circuit of the tube L00, however, it is amplified therein and causes a .change in the patch?- tial of the grids I2.I and I22. It is to be noted that the anodes I32 and I of the tubes I23 and I24 are supplied with alternating current and are maintained 180 degrees out vofphase since one anode is supplied from the primary and one from the secondary of the transformer I51. Since the signals supplied to the input terminals 46 and 41 are of 400 cycles due to the energization of the winding 39 from the .490 .cycle line 4| (Fig. 4) and the voltage and phase of this signal depends upon the relative position of the rotor winding 44, it is evident that the current flowing through one of the saturating windings I34, I42 will be increased when the other decreases, depending upon the phase relationship of the input signal. This will change the reluctance of the two magnetic paths and will unbalance the voltages produced in the secondaries .I3'I and I causing one voltage or the other to. predominate. Hence r the Signal supplied to the: output terminals 14 and 15 will constitute a ADO-cycle signal the am.- p itude and phase of which depends upon the input signal. This signal, as shown in Fig. .4, is supplied. to the control winding '12 of the torque motor 24 and will cause a torque to be developed in one direction or the other in the rotor 10 thereof depending upon the value and phaseqof ghe input signal received at the terminals .45 and In .a similar manner the signal supplied to the input terminals 51 and 5310f the amplifier pro.- duces an output. voltage at the terminals .5"! and .68 which is suited to produce a torque in the rotor ,60 of the torque motor 25 in a direction dependent upon the phasing of the input signal.

It will be noted that the current supplied to thecontrol windings -62 and 72 of the torque motors is dependent upon the signal strength.

' Hence the processing torque developed by the motors and the consequent rate of precession of the gyroscope is proportional to the relative angular displacement of the spin axis of the gyroscope from the pendulums. The correction rats is thus varied with the correction angle so as to obtain a, rapid and accurate vcorrection without hunting.

This correction ratemay be varied by adjustment of the motor excitation and of the control circults.

Due to the transformer I08, rectifier H0- condenser H I, a biasing voltage is built up across theresistor -I I 3 which varies with the signal volt.- age. This biasing voltage increases the negative bias on the grid I93 Of the tube I95) and when it reaches a certain value will block the tube 60 against further amplification of the incoming-signal. The transformer I08 is so designed that the tube I00 will become blocked when the incoming signal corresponds to a. predetermined deflection of the pendulum with. respect to the gyroscope. The system may be designed, lor' example, so that a five degree displacement of the pendulum produces a 1 /4 volt signal at the input terminals 46 and 41. In that event, if it is desired to cut off the pendulum control of the gyroscope when the displacement equals five degrees, the cut-off circuit may be adjusted to block the amplifier tube I when the signal at the input terminals exceeds 1% volts. When the amplifier tube I00 is thus blocked, equal space currents will flow into the tubes I23 and I24 and the secondaries I37 and I45 will again produce equal and opposite voltages and no resultant voltage will be supplied at the output terminals I4 and I5. No further torque is then developed by the torque motor 24 and the gyroscope becomes free until the relative angles return to a value at which the tube I60 becomes unblocked and allows the control circuit to again function.

The system thus prevents the gyroscope from following sudden and wide swings of the pendulums such as would occur in response to acceleration forces and produces a stable control. It is obvious that the two pendulums may be combined as a single pendulum mounted for universal movement and connected to actuate the two transmission units.

A switch I80 is connected to short circuit the primary I01 of the transformer I08 when it is desired to eliminate this cut-oil feature. With the switch I80 closed the input signal to the tube I00 will cause a precessing force to be applied to the torque motor 24 of the gyroscope whenever the signal is greater than zero. The switch I80 may be closed for example when it is desired to erect the gyroscope from a position more than five degrees from vertical. After the gyroscope has been brought into agreement within five degrees with the pendulum 30, the switch I80 may be opened to allow the control to operate automatically. Thereafter the precessing force will be applied to the gyroscope in response to any variation in the position of the spin axis from that of the corresponding pendulum 30, but the control will be automatically interrupted whenever the pendulum is caused to move excessively due for example to acceleration and deceleration forces. A similar effect is produced in the channel connected between input terminals 51, '8 and output terminals 61, 68 to interrupt the signal to the torque motor when the pendulum 28 is displaced by acceleration forces.

In Figs. 1, 2 and 3, the mounting of the gyroscope housing I0 and the pendulums 28 and is shown in greater detail than in Fig. 4. The trunnions I2 and I3 (Fig. 2) of gyroscope housing I0 are journalled in suitable bearings 202 and 203 mounted on the gimbal ring I4. The trunnion I3 and bearing 203 carry the rotor and stator respectively of the transmitter unit 23 which is of standard construction and includes stator and rotor windings and 5| (Fig. 4) either of which may be mounted to rotate with the trunnion I3. The torque motor 24 is mounted on a bracket 204 forming a part of the gimbal ring I4 and is geared by gears 205 and 206 to the trunnion I2. The torque motor 24 is likewise of standard construction and may comprise a two-phase induction motor of any suitable type having a squirrel cage rotor I0 and field windings II and I2 (Fig. 4).

As seen in Fig. 3, the trunnions I5 and I6 of the gimbal ring I4 are journalled in bearings 2 I 3 and 2 I 4 respectively carried by the frame I1. I'he trunnion I5 and bearing 2I'3 supportthe rotor and stator of the transmitter unit 22, which is the same asunit 23, and includes windings 38 and 39 (Fig. 4) either one of which may be mounted to rotate with trunnion I5. A torque motor 25 which is similar to the motor 24 and includes rotor 60 and field windings 6| and '62 (Fig. 4), is mounted on a bracket 2I5 carried by the frame IT. The rotor 60 is connected by gears 2l8 and 2I9 to trunnion I6. The frame I! is attached to the support I8 shown as a ring which is secured in a normally horizontal plane on the craft.

The unit 33 of the transmission system is mounted on a bracket 222 carried by the frame IT. The pendulum 30 is attached to the shaft 3I of the rotor of this unit. The mounting of the unit is such that the shaft 3| is positioned with its axis parallel to the axis of the trunnions I5 and I 6.

A similar unit 32 of the transmission system is mounted on a bracket 226 attached to the frame H. The shaft 29 of the rotor of unit 32 carries pendulum 23 and is mounted with its axis parallel to the axis of the trunnions l2 and I3. The units 32 and 33 are similar to the transmitter units 22 and 23, but are commonly known as control transformers because the rotor windings 44 and are connected to the grid circuit of an amplifier so that substantially no reaction is placed upon the controlling transmitter units when the respective rotors are displaced.

The support I8 is shown as carrying a top casing 230 and a bottom casing 23! which enclose the gyroscope assembly. The top casing 230 is provided with an opening 232 through which the action of the gyroscope may be observed and through which a suitable caging device may be inserted.

The pendulum 30 is pivoted by a pin 235 to a link 236 attached to the shaft 3| so as to permit limited swinging movement of the pendulum about an axis normal to the axis of the shaft 3|. A stop 23! is provided to limit the swinging movement of the pendulum 30 about the axis of the pin 235. The pendulum 28 is similarly mounted for swinging movement about an axis normal to that of the shaft 29. This freedom of movement of the pendulums 28 and 30 prevents any bending force from being applied to their respective shafts and reduces the frictional load on their respective bearings.

It will be noted that the above system provides a gyro-erecting control which operates continuously to maintain the gyro axis vertical and is prevented from following spurious swings of the pendulums due to external forces. The control rate is proportioned to the'error and may be readily varied by adjustment of the control circuits. The system is particularly suited for heavy aircraft.

Although a specific embodiment of the invention has been shown for purposes of illustration, it is to be understood that various changes and modifications may be made therein as will be readily apparent to a person skilled in the art. The invention is only to be restricted in accordance with the scope of the following claims.

What is claimed is:

1. A gyroscope erecting system comprising a gyroscope, gimbal means mounting said gyroscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by pivotal movement of, said symscope'abQut 9 the respectiveaxes, additional units .of said electrical synchronous transmission system connected to be actuated by pivotal movement of said pendulums about the respective axes, means interconnecting the respective units to produce signals representing angular deviations of the gyroscope from the positions of the pendulums, and torque motors responsive to said signals mounted to apply precessing torques to said gyroscope about :said axes so as to maintain a predetermined angular relationship between the spinaxis of said gyroscope and the positions of said pendulums.

.2. .A gyroscope erecting system comprising a gyroscope, gimbal means mounting said .gyroscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by pivotal movement of said gyroscope about the respective axes, additional units of said electrical synchronous transmission system connected to be actuated by pivotal movement of said pendulums about the respective axes, means interi connecting the respective units :to produce signals respresenting angular deviations of the gyroscope from the positions of the pendulums, torque motors mounted to apply precessing torques to said. gyroscope about-said axes, means responsive to said signals to energize said torque motors to apply said precessing torquesin direction to maintain a predetermined angular relationship between the spin axis of said gyroscope and the positions of said pendulums, and means responsive to a predetermined signal value to interrupt said energization and release said gyroscope from the control of said pendulums, 'whereby the gyroscope is prevented from following excessive swings .of said'pendulums.

3. A gyroscope erecting system comprising a gyroscope, gimbal means mounting said gyroscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by pivotal movement of said gyroscope about the respective axes, additional units of said electrical synchronous transmission system connected to be actuated by pivotal movement of said pen- :dulums about the respective axes, means interconnecting the respective units to produce signals representing angular deviations of the :gyroscope from the positions of the pendulums, torque motors mounted to apply precessing torques to said gyroscope about said axes, and "means including an amplifier channel responsive to said signals connected to energize said torque motors to apply said precessing torques in a direction to maintain a predetermined angular relationship between the spin axis of said gyroscope and the positions, of said pendulums.

4. A gyroscope erecting system comprising a gyroscope, gimbal means mounting said gyro- 10 connecting the respective units to produce signals of phase and value representing deviations in direction and amount of the gyroscope from the positions of the pendulums, torque motors mounted to apply precessing torques to said gyroscope about said axes, and means including an amplifier channel responsive to said signals connected to energize said torque motors to apply said precessing torques in a direction to maintain a predetermined angular relationship between the spin axis of said gyroscope and the positions of said pendulums, and means responsive to a predetermined signal value to block said amplifier channels so as to interrupt said energization and release said gyroscope from the control of said pendulums, whereby said gyro- .scope is prevented from following excessive swings :of said pendulums.

5. A gyroscope erecting system comprising a gyroscope, gimbal means mounting said gyroscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by pivotal movement of said gyroscope about the respective axes, additional units of said electrical synchronous transmission system connected to be actuated by pivotal movement of said pendulums about the respective axes, means interconnecting the respective units to produce signals representing angular deviations of the "gyroscope from the positions of the pendulums, said units each including rotor and stator windings, means energizing the rotor windings of the gyro-controlled units with an alternating voltage, leads connecting the stators of the yro-controlled units to the stators of the pendulum-controlled units, amplifier channels, leads connecting the rotors of the pendulum-controlled units to the inputs of said amplifier channels, torque motors including control windings and induction rotors mounted to apply precessing torques to said gyroscope about said axes, and leads connecting the outputs of said amplifier channels to enerscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by relative pivotal movement of said gyroscope and of said pendulums about the respective axes to produce signals of phase and value representing angular deviations of the gyroscope from the positions of the pendulums, said units including rotorand stator windings, "means energizing the rotor windings of the gyro-controlled units with an alternating voltage, leads connecting the stators of the gyro-controlled units to the stators of the pendulum-controlled units, amplifier channels, means connecting the rotors of the pendulum-controlled units to the inputs of said amplifier channels, torque motors including control windings and induction rotors mounted to apply precessing torques to said gyroscope about said axes, and means connecting the outputs of said amplifier channels to energize said control windings so as to cause said rotors to apply precessing torques for erecting said gyroscope, and means responsive to Signal 7 11 values representing a predetermined angular deviation of the spin axis of said gyroscope from the position of said pendulum to block said amplifier channels and release said gyroscope from the control of said pendulums whereby said gyroscope is prevented from following excessive swings of said pendulums.

'7. A gyroscope erecting system comprising a gyroscope, gimbal means mounting said gyroscope for pivotal movement about a pair of axes normal to each other, a pair of pendulums mounted to pivot about axes parallel to said first axes, units of an electrical synchronous transmission system connected to be actuated by pivotal movement of said gyroscope about the respective axes, additional units of said electrical synchronous transmission system connected to be actuated'by pivotal movement of said pendulums about the respective axes, means interconnecting the respective units to produce signals representing angular deviations of the gyroscope from the positions of the pendulums, torque motors mounted to apply precessing torques to said gyroscope about said axes, and means including an amplifier channel responsive to said signals to energize said torque motors to apply said precessing torques ina direction to maintain a predetermined relationship between the spin axis of said gyroscope and the positions of said pendulums, said amplifier channels including saturable core transformers having primaries energized from a source of alternating current, secondaries connected in opposition to supply energizing current to said torque motors, and saturating windings connected for balanced excitation and having means responsive to said signals to unbalance said excitation.

8. A gyroscope assembly comprising a gyroscope, gimbal means including trunnions mounting said gyroscope for movement about a pair of axes normal to each other, units of an electrical synchronous transmission system having rotors mounted to turn with said trunnions about each of said axes, a pair of torque motors mounted respectively for rotation about axes parallel to each of said first axes and means connecting said motors to apply precessing torques to said gyroscope about the respective axes, pendulous means mounted to swing about axes parallel to each of said first axes, units of the synchronous transmission system having rotors mounted to turn in response toswinging movement of the pendulous means about their axes, and means actuated by relative angular movement of the rotors of said units for energizing said first and second torque motors.

9. A gyroscope assembly comprising a gyroscope, gimbal means including trunnions mounting said gyroscope for movement about a pair of axes normal to each other, units of an electrical synchronous transmission system having rotors mounted to turn with said trunnions about each of said axes, a pair of torque motors mounted respectively for rotation about axes parallel to each of said first axes and means connecting said motors to apply precessing torques to said gyroscope about the respective axes, pendulous means mounted to swing about axes parallel to each of said first axes, units of the synchronous transmission system having rotors mounted to turn in response to swinging movement of the pendulous means about their axes, means including said synchronous transmission system responsive to the direction and amount of angular displacement between the rotors of 12 said first and second units to actuate said torque motors so as to apply precessing torques to said gyroscope which vary with said displacement.

10. A gyroscope assembly comprising a gyroscope, gimbal means including trunnions mounting said gyroscope for movement about a pair of axes normal to each other, units of an electrical synchronous transmission system having rotors mounted to turn with said trunnions about each of said axes, a pair of torque motors mounted respectively for rotation about axes parallel to each of said first axes and means connecting said motors to apply precessing torques to said gyroscope about the respective axes, pen dulous means mounted to swing about axes parallel to each of said first axes, units of the synchronous transmission system having rotors mounted to turn in response to swing movement of the pendulous means about their axes, means including said synchronous transmission system responsive to the direction and amount of angular displacement between the rotors of said first and second units to actuate said torque motors so as to apply precessing torques to said gyroscope which vary with said displacement, and means rendering said last means ineffective when said displacement exceeds a predetermined value whereby said gyroscope is prevented from following excessive swings of said pendulums.

11. A gyroscope assembly comprising a gyroscope, gimbal means including trunnions mounting said gyroscope for movement about a pair of axes normal to each other, units of an electrical synchronous transmission system having rotors mounted to turn with said trunnions about each of said axes, a pair of torque motors mounted respectively for rotation about axes parallel to each of said first axes and means connecting said motors to apply precessing torques to said gyroscope about the respective axes, pendulous means mounted to swing about axes parallel to each of said first axes, units of the synchronous transmission system having rotors mounted to turn in response to swinging movement of the pendulous means about their axes,

means including said synchronous transmission system responsive to the direction and amount of angular displacement between the rotors of said first and second units to actuate said torque motors so as to apply precessing torques to said gyroscope which vary with said displacement, means rendering said last means ineffective when said displacement exceeds a predetermined value whereby said gyroscope is prevented from following excessive swings of said pendulums, and manual means to render said last means inefiective so as to restore said spin axis from a displacement in excess of said predetermined value.

WLADIMIR A. REICHEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,942,737 Wood Jan. 9, 1934 2,382,993 Haskins, Jr Aug. 21, 1945 2,417,573 Strother Mar. 18, 1947 FOREIGN PATENTS Number Country Date 345,127 G eat Britain Mar. 19, 1931 

